Fix generate_data.py PermissionError: chown /app to user before USER switch

data/ was created as root; non-root user couldn't write JSON files to it.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Dockerfile

@@ -13,10 +13,10 @@ RUN pip install --upgrade pip && \
 
 COPY . .
 
-RUN mkdir -p data
-
 # Run as non-root user (required for HuggingFace Spaces)
-RUN useradd -m -u 1000 user
+RUN useradd -m -u 1000 user && \
+    mkdir -p data && \
+    chown -R user:user $APP_HOME
 USER user
 ENV HOME=/home/user
 ENV PATH=/home/user/.local/bin:$PATH